An extremely mild method for the transformation of propiolic esters to β-keto esters via thiol addition is reported, including its successful application to the synthesis of (±)-thienamycin.
A mild and efficient method for the conversion of propiolic esters to β-keto esters was developed. Initially, propiolic esters were converted to β-phenylthio-α, β-unsaturated esters, which were treated with N-bromoacetamide in an aqueous solvent followed by reductive debromination with an aqueous solution of sodium sulfite, affording β-keto esters in good yields. Using this new method, a formal total synthesis of (±)-thienamycin from 4-propargyl-2-azetidinone was accomplished.
Convenient synthesis of .alpha.-(2-oxoazetidin-4-yl) esters and ketones and related systems
作者:Robin P. Attrill、Anthony G. M. Barrett、Peter Quayle、Jan Van der Westhuizen、Michael J. Betts
DOI:10.1021/jo00184a001
日期:1984.5
Regioselective transformation of internal alkynes to unsymmetrical ketones. Novel routes to key intermediates for the synthesis of carbapenem and carbacephem skeletons